In my U.S. Pat. No. 4,679,786, UNIVERSAL EXERCISE MACHINE, issued July 14, 1987, I disclose as a preferred embodiment of an exercise machine a track-operated multi-pedal apparatus having four moving slides, each slide for operative connection to one of the limbs of the user. There are two endless chain means which travel in loops, each of the chain means selectively coupled to two of the slides. The endless chain means, which are driven by the slides during limb exercise by the user, are operatively connected to a flywheel which provides a resistance to the user during limb exercise.
Examples of other exercise devices of interest having movable slides or the like for operable connection to the limbs include U.S. Pat. No. 3,941,377 to Lie, issued March 2, 1976; U.S. Pat. No. 4,529,194 to Haaheim, issued July 16, 1985; and U.S. Pat. No. 4,618,139 to Haaheim, issued October 21, 1986.